Many of the genes strongly associated with autism spectrum disorder (ASD) risk encode chromatin modifiers that regulate gene expression during neurogenesis. SETD2 is an ASD risk gene that encodes the primary enzyme for catalyzing trimethylation of H3K36, although recent evidence suggests SETD5 may also have such a function. Methylation of H3K36 is highly conserved between yeast and humans and is associated with transcriptional fidelity and RNA splicing and DNA repair. The majority of individuals with SETD2 mutations present with both ASD and intellectual disability.
In the current project, Corey Harwell and his colleagues plan to use homozygous and heterozygous conditional knockout mouse models of Setd2 to examine the impact of loss of Setd2 function on the proliferation and cell fate specification of cortical progenitors, as well as the molecular regulation of developmental gene expression.
One major challenge to characterizing cell-type- and lineage-specific gene expression mediated by Setd2 is capturing relatively pure and developmentally synchronized neural progenitor populations. Harwell and his team plan to purify and collect the nuclei of isochronic progenitor cohorts during cell fate transitions. They then plan to process these nuclei for total RNA-sequencing and chromatin profiling, using the recently developed strategy, ‘cleavage under targets and release using nuclease’ (CUT&RUN), to examine genome-wide changes in chromatin and transcription dynamics. This approach will allow unprecedented temporal resolution of how Setd2 functions regulate chromatin dynamics and gene transcription during neuronal fate specification.
